1. Field of the Invention
The present invention relates to a technique of power saving control applied to electronic apparatuses such as personal computers.
2. Description of the Related Art
In recent years, various electronic apparatuses powered by both battery and an external source (AC commercial utility source) have been developed and come into widespread use. For example, portable (mobile) information terminals called PDAs (Personal Digital Assistants), notebook-sized personal computers or digital cameras are given as typical electronic apparatuses.
Recently, protection of the environment has attracted great interest; for example, the following study has been made to prevent global warming. Power consumption concentrating on the daytime is reduced (peak cut) and shifted (peak shift), and thereby, the environmental load of power generation facilities is made small.
In view of such circumstances, a mechanism to realize peak cut or peak shift is proposed in this kind of electronic apparatus (e.g., JPN. PAT. APPLN. KOKAI. Publication No. 2000-29576).
In general, this kind of electronic apparatus has the following large number of items for setting the system environment. For example, one is an item for turning off a monitor when a predetermined time elapses after the operation stops. Another is an item for turning off a hard disk when a predetermined time elapses after data access stops. A file called a profile collectively manages the items described above. Therefore, the profile is automatically changed in accordance with the time zone, and thereby, the above-mentioned peak cut and peak shift can be realized without increasing the cost.
However, correct automatic change of the profile in accordance with the time zone is not carried out in the conventional case. For this reason, a special mechanism for peak cut and peak shift is in fact independently and additionally provided.